How long do I wait before taking a complaint to the ombudsman?

The Energy Ombudsman will not normally look at a complaint you have not first given the company a fair chance to fix. The timings below apply to eligible microbusinesses and small businesses; check who can use the service first.

Step 1: complain to the company

Use the supplier's or broker's complaints process and make the complaint in writing, so you have a date. Say what went wrong, what you want (a corrected bill, a refund, an apology) and by when.

Step 2: the eight-week window

The Ombudsman says to allow the company eight weeks to resolve the problem. If it is still unresolved at the end of that time, you can take it to the Ombudsman.

The shortcut: a deadlock letter

If the company decides it can do nothing more, it should send a deadlock letter (sometimes called a final response). You can then escalate straight away without waiting for the eight weeks to run out.

The deadline after deadlock

Once you have a deadlock letter you must escalate within 12 months. Diarise the date on the letter.

Worked example

• 1 March: you email your supplier about an inflated bill.
• 1 March plus eight weeks (56 days) is 26 April. If nothing is resolved, you can go to the Ombudsman.
• If the supplier sends a deadlock letter on 10 April, you can go on 10 April, and you have until 10 April the following year.

Possible changes

In October 2025 the government proposed cutting the wait and strengthening the Ombudsman. Its consultation response of 17 June 2026 settled on six weeks rather than four, for households and eligible small business customers, to be brought in by Ofgem. The Energy Ombudsman described it on 18 June 2026 as a change that "will" happen. Giving decisions clearer legal standing needs legislation, which has no date. As of November 2026 we found no confirmed start date for the six-week wait, so assume eight weeks unless the Ombudsman's website says otherwise.

While you wait, keep paying the part of the bill you don't dispute and ask the supplier in writing to put the disputed part on hold. Our guide to disputing a high bill shows how.

More on the whole process is in the energy disputes guide.

What to put in your complaint

A clear first complaint speeds up everything that follows. Include:

• Your account number, MPAN or MPRN and the premises address.
• A short timeline of what happened, with dates.
• The exact outcome you want, with a figure if it is a refund.
• A request for a written response, and for the supplier to confirm when the eight weeks started.

If the company goes quiet

Silence is not a deadlock letter. Keep the date of your first complaint, chase in writing, and when eight weeks have passed you can go to the Ombudsman anyway. If the company sends a letter saying it will not do more, treat that as deadlock and start your 12-month clock.

What if you miss the 12 months?

We found no published information on exceptions. Don't rely on one: file well within the year and keep proof of the deadlock letter's date.